An initial application of plant genomics has been to monitor gene expression on a scale much larger than previously possible. Although multiplexed assays of RNA abundance have developed more quickly than those for protein and metabolite levels, some combination of these approaches will soon be providing our best views yet into plant molecular biology. Three techniques that have made contributions to the RNA transcript portion of this combination are reviewed. Currently, each can produce a profile of expression levels for a large but incomplete set of plant genes, at reproducibly high levels of accuracy and over a range of labor and financial expenses.